So, how does popcorn actually pop?
First of all, there are a few types of corn that are grown. But only one kind can be popped. Popcorn.
And the reason that popcorn can be popped is that the outer layer, the hull, is thicker than any other type of corn. This comes in handy when the kernel is heated up.
You see, each kernel of corn has a small amount of water inside as well as a little blob of starch. When the water is heated up it turns into steam. Super heated steam. The steam mixes with the starch and changes it into a gel like substance.
Now the steam continues to heat up and expand, this causes pressure on the hull of the corn kernel. Since the popcorn hull is thick, it contains the heat for a slightly longer time than other corn, giving the starch time to form into that gel like substance.
Once the pressure gets too high, the hull bursts open and the starchy gel expands outwards, cooling as it goes, forming the puffy, yummy substance we love to eat.
- Popcorn can jump up to 3 feet/1 meter into the air.
- There are two types of popped popcorn, Snowflake and Mushroom shaped.
- The oldest ear of popcorn was found in a bat cave in Mexico in 1948. It is believed to be over 5,000 years old.
- A kernel will pop when it reaches a temperature of 175 degrees Celsius.
- Popping popcorn is one of the most popular uses for microwaves.
What really stands out, particularly when you watch the videos, is that you don’t see borders and the many differences that divide us. Instead, what you see is the one, beautiful planet that we all share.
A wonderful example of this is astronaut Jeff Williams’ video of the Earth as he passed overhead during a recent visit to the International Space Station. This video, titled “Jeff’s Earth” is mesmerizing on a big HD TV:
This 2012 video titled “Earth Illuminated: ISS Time-lapse Photography” is another wonderful opportunity to see what the astronauts see from the ISS as they orbit the Earth:
It is easy to forget that the Earth is the only home we have and that we share it. Fortunately, photos and videos from organisations like NASA help remind us of what we have in common.
Here are some photos from the NASA Johnson Space Center collection on Flickr:
Featured image credit: NASA Johnson Space Center
When you drop a piece of molten glass into cold water, the result is a tadpole shaped piece of extremely hard glass.
Well, at least the head of the drop is very strong. The tail is actually quite delicate.
The reason Prince Rupert’s Drops are so strong is that the outer layer of glass hardens almost straight away, while the inside takes a bit longer. When hot glass cools down (and this happens with water turning into ice too), the glass shrinks. This means that the inside of the glass drop is cooling down and shrinking but the outside is already cold and hard so the glass pulls towards the centre of the drop and makes it really, really strong inside.
Before we look at a really cool video of Destin from Smarter Every Day trying to break one of these drops using a bullet, take a look at his video that shows you how the drop is formed.
Right, now you have seen how the drop is formed and that hitting it on the head with a hammer won’t break it but if you nip the tail then the whole thing explodes.
Destin takes it a step further and shows us that even a speeding bullet won’t actually break the head of the drop itself.
Tip: try watch this on a large, high resolution screen for an even better experience.
How cool was that?!
If you dropped a feather and a bowling ball at the same time, which would hit the ground first? You would probably say that the bowling ball would hit the ground first, right? After all, a bowling ball is so much heavier.
It turns out that the relative weight of the objects doesn’t make a difference to which object will hit the ground first, as strange as that may sound.
One of the parents in our class chat group shared this terrific video from the BBC that explains what really makes a difference and, surprisingly, that a bowling ball and a feather will hit the ground at the same time under the right conditions:
So, as you can see, the factor that makes the difference in normal conditions isn’t the objects’ weight, it’s air resistance! When you remove the air, both objects fall at the same rate and hit the ground at the same time.
Image credit: Pixabay
Understanding lightning better
Lightning is, at the same time, an awesome and terrifying phenomenon. It seems to affect us on a very primal level. Understanding it better helps us appreciate its awesome beauty while making sure we are safer during lightning storms. I found a great video from SciShow Kids about lightning:
National Geographic also has a great video that explains lightning:
Lightning moves pretty quickly so we don’t always see lightning in more detail. I found this terrific video on Wikipedia (your browser may not play the video if it doesn’t support .ogv formats):
So what happens when lightning strikes an airplane?
The prospect of lightning striking an airplane can be scary. I was fascinated to learn that planes are engineered to handle lightning strikes in an interesting way. Here is a video from the Smithsonian Channel:
If you are interested in reading more about how airplanes are engineered to withstand lightning strikes, also read an article on Scientific American titled “What happens when lightning strikes an airplane?”. Here is an extract from the Scientific American article that answer my daughter’s questions about passengers’ experience of a lightning strike:
Although passengers and crew may see a flash and hear a loud noise if lightning strikes their plane, nothing serious should happen because of the careful lightning protection engineered into the aircraft and its sensitive components. Initially, the lightning will attach to an extremity such as the nose or wing tip. The airplane then flies through the lightning flash, which reattaches itself to the fuselage at other locations while the airplane is in the electric “circuit” between the cloud regions of opposite polarity. The current will travel through the conductive exterior skin and structures of the aircraft and exit off some other extremity, such as the tail. Pilots occasionally report temporary flickering of lights or short-lived interference with instruments.
Thunderstorms are impressive and powerful natural phenomenon and it’s usually a good idea to keep your distance, regardless of your mode of travel. At the same time, it is good to know what even when you are suspended in the air, traveling through a storm, you are probably safe.
Featured image credit: Pixabay
Did you know that knowing the size of raindrops in clouds can help meteorologists more accurately predict rainfall? A new joint American and Japanese mission promises to help scientists make even more accurate predictions based on the size of the raindrops in clouds. This next video is a great overview of the mission:
According to NASA’s Goddard Media Studios blog post titled “GMS: Why Do Raindrop Sizes Matter In Storms?”:
Not all raindrops are created equal. The size of falling raindrops depends on several factors, including where the cloud producing the drops is located on the globe and where the drops originate in the cloud. For the first time, scientists have three-dimensional snapshots of raindrops and snowflakes around the world from space, thanks to the joint NASA and Japan Aerospace Exploration Agency Global Precipitation Measurement (GPM) mission. With the new global data on raindrop and snowflake sizes this mission provides, scientists can improve rainfall estimates from satellite data and in numerical weather forecast models, helping us better understand and prepare for extreme weather events.
If you are curious about the spacecraft that is conducting this amazing survey work, here is a helpful explanatory diagram:
Here is a great video that explains how the size of raindrops can help better understand storm behaviour:
This is a fascinating mission. I didn’t realise just how much storm prediction can be improved by understanding how big raindrops are.
Hi everyone, its the mom here, with my first Stuff to Teach Our Kids post.
I really like baking, the kids like mixing and licking the bowl. I also like teaching them how and why we mix the ingredients together and the reactions that take place when certain things mix. Baking really is just science. So I went looking for some fun baking experiments we could try.
I came across this video by The Crazy Russian Hacker about what happens to marshmallows in a vacuum. It looks like a really fun experiment to try at home and you can find a vacuum box like the one he uses on Amazon here. You can also make your own vacuum box using a wine bottle and a wine saver pump/stopper (instructions here).
According to Physics.org the science behind the growing marshmallows is as follows:
Marshmallows have small bubbles of air trapped inside them. These bubbles are at atmospheric pressure. When the air inside the glass container is sucked out, the volume of the container remains the same although there is much less air inside – so the pressure is reduced. The air bubbles inside the marshmallows are therefore at a much higher pressure than the air surrounding the marshmallows, so those bubbles push outwards, causing the marshmallows to expand. When air is let back into the glass container, the surrounding pressure increases again, and the marshmallows deflate back to their normal size.
As soon as we get the vacuum boxes we are going to try this out for ourselves and I will post a video of our results. Please let us know if you try it out too.
Mars Reconnaissance Orbiter (MRO) is a multipurpose spacecraft designed to conduct reconnaissance and exploration of Mars from orbit. The US$720 million spacecraft was built by Lockheed Martin under the supervision of the Jet Propulsion Laboratory (JPL). The mission is managed by the California Institute of Technology, at the JPL, in La Cañada Flintridge, California, for the NASA Science Mission Directorate, Washington, D.C. It was launched August 12, 2005, and attained Martian orbit on March 10, 2006. In November 2006, after five months of aerobraking, it entered its final science orbit and began its primary science phase. As MRO entered orbit, it joined five other active spacecraft that were either in orbit or on the planet’s surface: Mars Global Surveyor, Mars Express, 2001 Mars Odyssey, and the two Mars Exploration Rovers (Spirit and Opportunity); at the time, this set a record for the most operational spacecraft in the immediate vicinity of Mars. Mars Global Surveyor and the Spirit rover have since ceased to function; the remainder remain operational as of March 2016.
MRO contains a host of scientific instruments such as cameras, spectrometers, and radar, which are used to analyze the landforms, stratigraphy, minerals, and ice of Mars. It paves the way for future spacecraft by monitoring Mars’ daily weather and surface conditions, studying potential landing sites, and hosting a new telecommunications system. MRO’s telecommunications system will transfer more data back to Earth than all previous interplanetary missions combined, and MRO will serve as a highly capable relay satellite for future missions.
I noticed a terrific video commemorating 10 years of the MRO’s mission which includes some wonderful imagery:
You can also find a huge gallery of high resolution imagery in the NASA JPL Photojournal that is worth spending some time exploring. Here are some examples:
Image credit: Wikipedia (Public Domain)
I just watched another episode of Cosmos: A Spacetime Odyssey (finally available on iTunes!) about Michael Faraday and his discoveries about electromagnetism. Faraday was the director of the Royal Institution and started its annual Christmas Lectures back in 1825:
Begun by Michael Faraday in 1825, the CHRISTMAS LECTURES are now broadcast on UK television every December and have formed part of the British Christmas tradition for generations.
The Lectures have taken place every year since they began, stopping only from 1939 to 1942, when it was too dangerous for children to come into central London. The theme changes every year, and they are delivered by an expert in their field.
The reason why I am telling you this is because the Royal Institution has a wonderful collection of videos available on YouTube and its website, many of which are great for kids. One example is this Christmas Lecture by the late Carl Sagan about human space travel:
If you haven’t subscribed to their YouTube channel, definitely do that. It looks like it could be a source of inspiration for sure. Here is a playlist titled “RI Talks” which includes a collection of talks about a range of fascinating topics:
This talk by Andrew Szydlo titled “Fireworks and Waterworks” looks like a lot of fun and I can’t wait to watch this with our kids.
I have a feeling this channel will become my Saturday morning entertainment once I finish watching Cosmos: A Spacetime Odyssey (again).